Coil form



Dec. 3, 1963 v w. F..s'rAH| 3,112,898

COIL FORM Filed June 4, 1962 United States Patent 3,112,898 COlL FORM William F. Stahl, 423 Ahhotts Fork Road, Kenilworth, lll. Filed .lune 4, 1962, Ser. No. 199,684 2 Claims. (Cl. 242-`118.7)

This invention relates to a coil form, and, more particularly, to a separable frame upon which electrical wiring is wound so as to serve as an inductor;

he device with which the invention is concerned is variously termed bobbin or spook andk is characterized by a tubular body equipped with end anges, see, for example, applicants prior Patent No. 2,375,704.

lt is a general object of this invention to provide a novel coil form and, more particularly, a coil form made up of identical halves which are advantageously produced by molding of plastic materials. Y

Another object 'of this invention is to provide a twopiece coil form made up of halves uniteable along a longitudinal line of separation and which is characterized by advantageous dimensional stability.

Still another object of the invention is to provide a novel lockable joint between the two longitudinal halves of a coil form or bobbin. Other objects and advantages may be seen in the details of construction and operation set down in this specification.

This invention will be explained in conjunction with an illustrative embodiment in the accompanying drawing, in which FIG. l is a perspective View of the assembled formof the invention;

FIG. 2 is a perspective view of one identical half of the form seen in FIG. l;

FlG. 3 is a plan view of theFlG. l assembly;

PEG. 4 is a side elevational View of the assembled form seen in FIG. 3;

FlG. 5 is a sectional view, taken along the sight line 5-5 of FlG. 4; and

FlG. 6 is a fragmentary sectional view, in enlarged scale, such as would be seen along the sight line 6-6 of FlG. 3.

Referring to the drawing, the numeral 10 designates generally the inventive coil form, which is seen to be made up of two longitudinal halves 11 and 11. The halves 11 and 11 are identical, and cach includes a tubular body Y or spool portion 12 and 12 equipped with integral end flanges 1.3, 13 and 14, 14. The body portions 12` and 12 are seen to be U-shaped in transverse section so that when the two parts 11 and 11 are joined together, a rectangular cross section is evolved. ln similar fashion, the llanges 13, 13 and 1d, 1d are generally rectangular, and when united as seen in FIG. l define rectangular end flanges. lt

will be immediately apparent that in some installations the cross-sectional conguration of both the assembled spool portions il, l2 and the flanges 13, 13 and 14, 14 may be square rather than rectangular.

Each ange 13, 13' and 14, 1d is equipped with corner openings 13a and 14a for mounting and for receipt of the wire connectors to the conduits (not shown) wound on the assembled spool parts 12, 12 .between the assemled ilanges 13, 13 and 1d, 14.

As best seen in PFG. 2, each half v11 isV equipped with shoulders S and T which define reduced thickness areas 15 and 16 on one side of the flanges 125 and 13 and re- "ice 2 duced thickness portions 17 and 18 on the other side of the two flanges, ie., the side associated with the shoulder T. The shoulder S develops a reduced thickness portion 19 in the body 12, while the shoulder T develops l a reduced thickness section or area Ztl'in the body 12.

Each of the reduced thickness areas in the anges 13 and 14, i.e., the portions 1S-1S, 15-18, are equipped with a detent 21.

It will be seen that the shoulder S is on the inside or confronting faces of the ilanges 13 and 1d, while the shoulderT is on the `outside of these two flanges. The shoulder S is continuous, as is the shoulder T, so that the areas 17, 2i) and 1S effectively define what might be considered a male fitting or joint portion, while the areas 15, 19 and 16 deline a female fitting. Thus, each part 11, 11 is hermaphroditic. Both the male and female 'fittings are seen to be U-shaped when viewed from the side, and

mate with cooperative tting portions on the complemental halt'. However, each `half is identical, so that the coil forms can be mass-produced by conventional molding methods. The detents 21 are mutually engageabie to provide a rigid coupling so that the coil forms can be mass mounted on a mandrel for simultaneous winding with the assembled spool parts 12, 12. being dimensionally stable. For example, the detent 21 on the portion 16 of one half 11 mates with the detent 21 provided on the portion 18 lof the other half l11 (see EEG. 6).

As a speciiic example of the invention, the form 1li vwas constructed of fairly rigid polyethylene having a thickness of about 0.050. The reduced thicknes portion` 15-20 were all about 0.025" in thickness. Thus, there was sufficient give or resilience to permit the detents 21 to mutually engage. ln the illustration given,

the assembled llanges 13 measured 2 x l1/2, and the t assembled body 12 l x 5%". The shoulders S and T were spaced 7&2" back from the edge at the open side of the body 12. Preferably, the reduced thickness pertions 15-20 are about one-halt the thickness of the other portions ofform 1li, of the order of 0015-0030 as con.- pared to 0030-0060.

While, in the foregoing speciication, a detailed description of an embodiment or the invention has been set down for the purpose of iilustrationthereof, many variations in the details herein given may be made by those skilled in the art without departing from the spirit and scope of the invention.

`l claim: y

l. A coil form,L comprising a pair of mating parts, with each part including an essentially rigid plastic body having three connected sides providing a U shape in transverse section and dening an open mating side, y said body at eachend being equipped with an integral transverse ange extending peripherally outwardly from each side to provide parallel llanges having inside surfaces in confronting relation, said body and anges adjacent said open side being equipped with a pair of perimetric shoulders adjacent to said open side to provide reduced thickness portions, each shoulder commencing at the periphery of` one of said flanges and continuing to the periphery of the other flange, one shoulder including an intermediate portion extending along the outside of said body and d end portions extending along the inside surfaces of of the order of one-half the thickness of the remainder of said flanges, the otherysh'oulder including an intermethe form. diate portion extending along the inside of said body and end portions extending along the outside surf Referelle Cid in the fil@ Of this Patint faces of said aiges whereby identical mating 5 UNITED STATES PATENTS shoulders are provi ed in said parts, and

2. The structure of claim in which said form is con- 2787743 Hllztrg/nf meteo of polyethylene having a thickness of the order 2,358,999 Guenter NOV. 4, 1958 of 0.03 @-0.060, with the reduced thickness portions being 

1. A COIL FORM, COMPRISING A PAIR OF MATING PARTS, WITH EACH PART INCLUDING AN ESSENTIALLY RIGID PLASTIC BODY HAVING THREE CONNECTED SIDES PROVIDING A U SHAPE IN TRANSVERSE SECTION AND DEFINING AN OPEN MATING SIDE, SAID BODY AT EACH END BEING EQUIPPED WITH AN INTEGRAL TRANSVERSE FLANGE EXTENDING PERIPHERALLY OUTWARDLY FROM EACH SIDE TO PROVIDE PARALLEL FLANGES HAVING INSIDE SURFACES IN CONFRONTING RELATION, SAID BODY AND FLANGES ADJACENT SAID OPEN SIDE BEING EQUIPPED WITH A PAIR OF PERIMETRIC SHOULDERS ADJACENT TO SAID OPEN SIDE TO PROVIDE REDUCED THICKNESS PORTIONS, 